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time, shall subjoin by the way, the powers and actions which accrue to bodies from such compressions and dilatations.

But

And as I well know how difficult it is in the present state of the mind to acquire a familiarity with nature now from the very elements, I shall add my own observations, in order to excite the attention and raise the thoughts of others. with respect to demonstration, whether as to the discovery of the density and rarity of bodies, I have no doubt that, with respect to thick and palpable bodies, the motion of gravity, as it is called, can be assumed as the best as well as readiest proof; for the gravity of a body will be in proportion to its compactness. But after we have come to the class of ethereal and spiritual substances, then indeed we have no measure or rule whereby to go, and shall need another method of investigation. But we will begin with gold, the heaviest of all bodies within our knowledge, (for philosophy is not yet so matured as that we ought to venture an opinion respecting the bowels of the earth,) and embraces the greatest quantity of matter in the smallest space; and we shall apply the ratios of other bodies to the sphere of this; intimating, however, that here we scarcely touch upon the history of weights, except as far as it may throw light upon the demonstrating of the dimensions of bodies. But as our design is not to publish conjectures, but to discover and gain knowledge, and this appears to lie in the examination and proof of the first experiments, I have determined in every very subtile experiment to subjoin the mode of experiment I have made use of, that after it is clearly ascertained how each thing by itself appears to me, men may see how far they may rest satisfied, and what further remains to be done, whether in the correction of errors which may still cleave to the work, or in the calling forth and employing of more accurate modes of proof. And I will for my own part diligently and sincerely intimate those subjects which appear to me to be less satisfactorily explored, and to lie, as it were, nearer and more open to error. Lastly, I will add my own observations, as I before said, so that whilst every part of philosophy is preserved entire, I may yet even by the way turn the face itself of natural history toward philosophy. It will be my care also to remark whatever those things are, whether experiments or observations, which occur and intervene beside the scope of inquiry, and pertain to other denominations, that the investigation may be kept distinct.

A TABLE OF THE CONJUNCTION AND EXPANSION DIES, WITH A CALCULATION OF THEIR RATIOS

OF MATTER THROUGH SPACE IN TANGIBLE BO

IN DIFFERENT BODIES.

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The Mode of Experiment upon the above Table.

Let the weights which I have used be understood to be of the same kind and computation with those of goldsmiths', a pound being twelve ounces, and an ounce twenty pennyweights, a pennyweight twenty-four grains. I have chosen gold as a standard of the ratios of other bodies, according to the measure of its extension, not so much because it is the heaviest of bodies, as because it is the most unique. For, other bodies, which, in some degree, partake of inconstancy even after they have been tried by fire, retain a diversity of weight and dimension; but pure gold

appears to be entirely free from this property, and to be the same in all circumstances. The experinent adopted in this case was this: I made an ounce of pure gold into the form of a cube; I then prepared a small square vessel to receive that body of gold, and to agree with it exactly, except that it was a little too high; yet, so as that there might be marked, by a distinct line, a space within the vessel in which the gold cube might ascend. I did that for the sake of fluids, that, when any fluid was to be put into the same vessel, it might not flow over, but, by this method, be more conveniently preserved in an accurate measure. I had, at the same time, another vessel made, in size and weight equal with the former, that, in a like vessel, the ratio of the contents of the body might appear by itself. Then, I had made cubes of the same magnitude or dimensions in all those materials specified in the table, which were capable of division. But, the fluids I made use of at the time, by filling the vessel until the fluid ascended to the place that was marked; and the powders in the same manner; but those as closely pressed as possible; but this with an especial view to their lying even and not suffering injury. The proof, therefore, was no other than that, one of the vessels being empty, should be put with an ounce in one scale, another of the vessels in another, with a body in the lump, and the ratio of the weight be taken; so that, in the proportion of its diminution would the dimensions of the same body be increased. For example, when a cube of gold gives one ounce, but one of fat a pennyweight, it is clear that the extension of the body of gold, compared with the extension of the body of fat, has a twentieth ratio. It was desirable, also, that the mode should be noted down of the measure which comprehended an ounce of gold; it was that of a pint of wine, according to English measure, a fraction a little less than two hundred and sixty-nine. The proof was this: I marked the weight of the water which was in the vessel, under the line aforesaid, and then the weight of water contained in a pint, and collected the ratios of the measures from those of the weights.

Cautions.

Observe whether, perchance, a closer contraction of the body from the united force produce a greater ratio of weight than is in proportion to the matter, whether or not this be the case, will appear from the peculiar history of the weight. If it should be so, the calculation is certainly erroneous, and the more bodies are extended, so much the more of matter they possess, than is in proportion to the calculation of weight and measure which depends upon it.

The smallness of the vessel which I made use of, and the form of it, although very convenient for the receiving of the beforementioned cubes,

was not equally suitable for the taking of the ratios with the strictest accuracy. For it could not well receive particles beneath a half or a quarter of a grain, and that square surface, in a small and imperceptible ascent or altitude, was capable of attracting a remarkable difference in the weight contrary to what it is in vessels rising to a point.

3. There is no doubt, that very many bodies noted in the table receive more or less within their species, according to weight and dimension. For, waters, wines, and the like, differ from one another in gravity. Therefore, as it respects the minutest calculation, the thing itself receives some modification; neither can the individuals, upon which our experiment falls, decide with exactness the nature of the species, nor, perhaps, agree minutely with experiments made on others. 4. I have set down in the above table those bodies which could conveniently fill the space or measure, each with its body in the lump, and could, as it were, be assimilated, and from the ratios of the weight, of which a judgment might be formed respecting the collection of matter. Three kinds of bodies, therefore, could not be brought into our computation; first, those which would not satisfy cubical dimension, such as leaves, flowers, fibres, membranes; 2dly, bodies with unequal pores and cavities, as sponges, fleeces, and cork; 3dly, pneumatic bodies are without weight.

Observations.

The collection of matter in those tangible bodies which have come under my observation, is within the ratios of twenty-one parts, or thereabout. The collection of matter is found most compact in gold, and most expanded in spirits of wine, (we speak of bodies which are whole and not porous.) For spirit of wine occupies a space twenty times, and that repeated, of the space which gold does, according to the ratios of one ounce to twenty-two grains. For, of those twenty-one parts, of which some are more compact than others; metals occupy thirteen parts, for tin, the lightest of metals, is almost eight pennyweights, thirteen, that is to say, below that of gold. For, all this kind of variety, leaving metals, is confined within those eight remaining parts, and, again, that remarkable variety which, by beginning inclusively from stones, is extended to those other subjects, is confined within three parts only, or but little more. For the touchstone, the heaviest of stones, (excepting the loadstone,) preponderates by little more than three pennyweights. But spirit of wine, the limit of levity in compact bodies, is lighter by little less than one pennyweight. A great gap presents itself from gold and quicksilver to lead, namely, from twenty pennyweights and a little under, to less than twelve. And, although great metallic bodies

ries are found, whether it be higher ground or whether lower. And in the same manner as to stones and diamonds that are crystals, whether the stony nature penetrate the earth so deeply as the metallic, or rather attaches only to the surface, which appears the more probable supposition.

abound in variety, I am not inclined to suppose | sideration the region in which the mines or quarthat there are any intermediate bodies, excepting, perhaps, the elements of quicksilver. From lead there is a gradual ascent to iron and tin. Again, there appears a great hiatus between metals and stones, namely, from eight to three pennyweights; for such, or about such, is the distance from tin to the touchstone. Only between these comes the loadstone, and almost on a par, and this is a metallic stone; and, probably, other fossils may be found of imperfect mixture, and of a nature compounded between stone and metal. From stones, indeed, to the other bodies, there is a gradual variation.

But we little doubt that, as to vegetables, and also in the parts of animals, they show themselves more than other bodies, although of sufficiently equal texture, which surpass spirit of wine in lightness. For, even the wood of the oak, which is firm and solid, is lighter than spirit of wine, and the wood of the fir much more. And very many flowers and leaves, and membranes and fibres, as the skins of serpents, the wings of insects, and the like, would doubtless approach the lesser ratios of weights, (if they were capable of cubic dimension,) and much more artificial substances, as tinder, the leaves of roses after distillation, and the like.

We generally find, as to the parts of animals, some bodies more compact than in plants. For, bones and skins are more compact than woods and leaves; for, we must correct that proneness which the human mind entertains toward conjecturing that bodies are hard and consistent, in proportion to their compactness and solidity, but that fluids are naturally less contracted. For, a collection of matter is not less in fluids than in solids, but rather more. Gold, by a certain softness which it possesses, verges to a fluid state, and, when liquefied, is not extended, but is contained within its former place. And quicksilver flows of itself, and lead easily flows, iron with difficulty, of which the one is a very heavy, the other a very light body. But this is especially to be noted, that metals which are frangible (fluids, to wit) far exceed stones in weight.

It is very remarkable of gold and quicksilver, which are so much heavier than other metals, that they are found sometimes in grains and small particles, as if perfect by nature and commonly pure, which happens to no other metals, which must unite and be purified by fire, whereas these two, the conjunction of which is by far the greatest and the strictest, is natural and without the aid of fire.

In the investigation of the nature of metals and stones, some inquiry should be made respecting those metals which are found lower than others and are deeper in the earth, as to whether there is any certain rule and standing experiment on this head. But here we must take into the con

Sulphur, commonly deemed the father of metals, though generally not so by the learned, or sulphur transferred to a kind of natural and not common sulphur, has a collection of matter inferior to every kind of metal and even to stones and the stronger earths, by two pennyweights and two grains; and yet, (if other circumstances concur,) if mixed up with mercury, on account of the admirable gravity of this latter, it could give the weights of all metals according to the ratio of the temperament, except the weight of gold.

The efficient of conjunction in bodies is not always considered in respect to their accumulation. For glass, which joins by means of a fierce and powerful fire, outweighs crystal, which is its original nature, and is extracted without fire or apparent heat; for as to ice being a solid, that is a popular error, and crystal itself is much heavier than ice, which is plainly kept together by cold, and yet it floats upon the water.

The mixture of liquors does not depend upon or arise from the ratios of their weights only, since the spirit of wine is not mixed with distilled oil of almonds, but (what would not appear probable) floats upon oil as oil upon water; and yet (as may be seen from the table) is only lighter by a grain and a half. But at the same time spirit of wine is by far more easily mixed with the spirit of water, though heavier; and as water itself is more easily mixed with oil of vitriol than with oil of olives; and yet oil of vitriol is heavier than water by eighteen grains, but oil of olives lighter by four. But this is not to be received without a particular consideration of the weight in bodies proportioned according to the mixture. For we see that wine floats upon water, if the agitation is repressed or there is a perturbation of the descent or first state; as when into a vessel in which water is contained you pour wine, but with a piece of bread or cloth intervening, which would break the power itself of the first condition. And the same takes place in water poured upon oil of vitriol with this design. And what is more; although wine be first poured in and afterwards water (upon the bread or cloth as aforesaid,) it finds its own place, and passes through the wine and settles itself.

Continuation of the History of the Conjunction and

Expansion of the Matter in the same Body.

I deem that our investigation into the ratios of powders will be attended with greater utility if we compare them with the bodies themselves, in their complete state, and do not consider them

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simply by themselves. For by this means a Judgment may be formed respecting the difference of the bodies and concerning those connexions and chains of their perfect nature which are the closest. But in the ratios of powders, we understand powders as compressed as possible. For this conduces to their evenness, and does not suffer accident. Mercury in the lump has in that experimental measure on which the table proceeds, 19 dwt. and 9 gr., but sublimated in powder, 3 dwt. and 22 gr.

to ashes; it both loses a great part of its weight. and the ashes do not by a considerable proportion fill the measure of the wood.

The method of pulverization has considerable influence with respect to the opening or expanding the body. For there is one ratio of powder which is produced by simple bruising or filing, another of that which is produced by distillation, as of sublimate; another of that which is produced by turning it, as it were, into rust by means of aquæ fortes, and consumptions; another of that which

Lead in the lump, 12 dwt. 14 gr., but in white is produced through fire, as cinders, calx. When lead, in powder, 4 dwt. 8 gr.

Steel in the lump, 8 dwt. 10 gr., but in prepared powder, (such as is used in medicines,) 2 dwt. 9 gr.

Crystal in the lump, 2 dwt. 18 gr., in powder, 1 dwt. 20 gr.

these, therefore, are under consideration, they will not admit in any way of comparison.

It is not my design to dwell longer on each particular subject than is requisite in order to my present undertaking; I cannot, however, refrain from intimating by the way such others as would

Red sandal in the lump, 1 dwt. 5 gr., in pow- facilitate it, though not absolutely demanded in der, 16 gr.

this place: especially I would propose that a

The wood of the oak in the lump, 19% gr., in table should be made of bodies with their pores, ashes, 1 dwt. 2 gr.

But that the ratios of powder pressed and not pressed may be the better understood, and that according to the difference of the bodies, I have taken the weight of roses in powder, since it could not be taken into the table in the lump: that gave in powder not pressed, 7 gr., in powder pressed, 22 gr., but at the same time in the wood of the tried red sandal, red sandal in powder not pressed, 10 gr., pressed, 161, so that powder of rose is much lighter than that of sandal if not pressed, heavier if pressed. I have also taken, as a supplement to the former table, the ratios of powder in some examples from flowers, herbs, and seeds, (for the dimension of roots could not be cubic,) for an example of the rest in their own species; and I find that the powder of rose-flower, as aforesaid, gives 22 gr., of sweet marjoram, 23, of sweet fennel, 1 dwt. 31 gr. I have taken also in powders the weight of other bodies which could not have been taken into the table, as of white sand. This gave I dwt. 20 gr.; of common salt, 1 dwt. 10 gr.; of sugar, 1 dwt. 2 gr.; of myrrh, 1 dwt.; of benjamin, 1 dwt. In this same table you may see that sulphur, in the lump, yields 2 dwt. 2 gr., in chymic oil, 1 dwt. 18 gr.; but vitriol in the body, 1 dwt. 22 gr., in oil, 1 dwt. 21 gr.; wine in the body, 1 dwt. 2 gr., and distilled, 22 gr.; vinegar in the body, 1 dwt. 2 gr., distilled, 1 gr. 1 dwt.

Cautions.

When we speak of weight in the body, and in the powder, we do not understand it of the same Individual, but of the body and powder of the same species contained within the same tabular

measure.

For if the wood of the oak be taken and at the same time the wood in the individual be reduced

with each body with its powders, calcinations, vitrifications, dissolutions, and distillations.

We leave to the proper history of weights the history of the variation of weights in individuals, that is, of the same body in the lump and in powders, as of water in snow or ice, and the same dissolved, of an egg raw and prepared for food, of a fowl alive and dead.

Observations.

In more compact bodies the compactness of the parts is much closer than to admit of being equalled by any position or pressure of its powders. And in proportion to the gravity and solidity of bodies is the difference between the whole bodies and their pores, as the ratio of quicksilver in a state of nature to quicksilver sublimated in powder is fivefold or more; the ratios of steel and lead do not ascend to fourfold; the ratios of crystal and sandal do not ascend to twofold.

In lighter and porous bodies there is perhaps a looser position of the parts in the bodies in their whole state than in their compressed powders, as in dry rose-leaves. And in bodies of this kind there exists a greater difference between their powders pressed and not pressed.

The parts of powders can so sustain themselves that powder not pressed will fill a measure thrice that of powder pressed.

Metallic bodies, as sulphur or vitriol, turned into their oils, retain their weight to a remarkable degree. There is not, indeed, a great difference between the oils and the bodies themselves. Doubtless by distillation they are attenuated and lose in weight: but this is the case with wine in a double degree to what it is with vinegar.

The pore in sublimated powder, as compared with that in the body in its natural state, is

worthy of notice from this circumstance, that although so great, (for it is as I have said fivefold,) and that not in a transient, as in the vapours of quicksilver, but in a consistent body, it returns without difficulty to its former orbit.

Continuation of the History of the Conjunction and Expansion of Matter through Space in the same Body.

Animals in swimming depress the water with their hands or feet; that being depressed, rises above its natural consistency, and bears up the body rising upon it. But skilful swimmers can so balance themselves upon the water, as to keep themselves up for a time without moving their arms or legs; nay, to walk upright and on the water, and perform other feats of agility.

Waterfowls, indeed, are webfooted, and so can conveniently depress the water with the membranes of their feet; but can swim better in deep

water.

Birds in flying beat and condense the air with their wings, but the air, (as was said of water,) restoring itself to its own consistency, carries the bird. And birds also sometimes cut their path with expanded wings, but retained in one position, or now and then striking their wings a little and then returning to their gliding motion. And there is an analogy between winged animals, whether feathered or not. For flies and all creatures of that kind have their membranes of wings with which they beat the air. But the weakness of their wings is made up by the lightness of their bodies. Winged creatures are more easily borne up aloft, especially those which have broader wings, as the swallow, though their motion is not so swift. And all birds which are of considerable magnitude have more difficulty in the first stage of their flight, in elevating themselves from the earth, since the air is of course not so deep.

Caution.

The motion of condensation in water, or air, or the like, is manifestly through striking or moving upon it. The parts of air or water, the farther they are from the first stroke or impulse, the weaker they are struck, and the slower they give way; but as they are nearer, so much the more forcibly and quickly; whence it necessarily happens that the anterior air, which flies with more rapidity, comes up to the posterior air, which is slower in its course, and so they come together. But since a greater condensation than is natural results from their conjunction, the bodies of water or air leap back and return, in order to open and loose themselves.

History.

The face of water and of every fluid is uneven after agitation and perturbation, and that by an

inequality movable and successive, till the water regains its proper consistency and is freed from the pressure: as in the waves of the sea and of rivers, even after the winds have calmed, and in all disturbed water.

winds also, which roll themselves together in the The same kind of inequality is evidently in the same manner as the waves: neither do they return to tranquillity immediately on the cessation of the first impetus, except that in the undulation of the air, the motion of gravity, which in water is joined with the motion of liberation from pressure, does not intervene.

A stone thrown sidelong on the water (as boys do in play) leaps off and repeatedly falls, and is struck again by the water. Swimmers when from an eminence they leap headlong into the water, guard against dividing it through the joining of their thighs. Lastly, water struck by the hand or by the body with power, beats like a ferula or any rather hard body, and causes pain. And in skiffs and keels of vessels which are guided by the force of oars, the water pushed forward and borne down by the oars behind the rowers forces the skiff forward, and makes it move on its way, and bound onward, as a boat is moved off from the shore by the waterman's pole. For the water, gathering itself behind the stern of the vessel and urging it into a contrary direction, is not the principal cause of this, which nevertheless arises from the pressure relaxing itself.

Air, in avoiding compression, imitates and puts forth all the actions of a solid body; as we may see in the winds, which direct the courses of ships, overthrow houses and trees, and prostrate them to the ground.

The stroke that is given from a sling, hollow and long, so as to help the compression of the air, is owing to the same cause.

Boys in imitation of cannon scoop out the wood of the alder tree and stop up each end of a squirt with bits of the root of the fleur de luce, or of paper rolled up, and then shoot off the little ball by means of a wooden pin, but before that touches it, the further ball is sent off with an audible force by the power of the air shut up in the squirt.

Air forcibly condensed becomes colder and seems to approach nearer the nature of water, as when we raise the wind with a fan, we perceive the air with a hurried motion by pressing forward, beating back again, or as when by drawing our lips together, the breath becomes cold, or as may be seen in bellows.

And when in the open air, you will find that it is much cooler when the wind is blowing than when the air is perfectly calm.

In the generation of sounds air condensed imtates the nature of a solid body, for, as between two solid bodies sound is produced by percussion,

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